For understanding of underlying problems of the invention, firstly reference is made to FIG. 32 schematically showing a conventional veneer reeling apparatus which is disclosed by Publication of Unexamined Japanese Patent Application (Kokai) 57-53306 of 1982.
This apparatus has a plurality of endless belts 151 for conveying veneer sheet 150, each trained round a driven front pulley disposed swingable as indicated by double-headed arrow about a pivotal axis defined by a rear pulley (not shown) located on opposite side of the belts 151. The reeling apparatus further includes a take-up reel 153 extending above the upper legs of the belts 151 for winding thereround veneer sheet 150 into a roll 154 and a plurality of sectional touch rolls 152 mounted on a shaft provided just below the reel 153. Each sectional touch roll 152 is located between any two adjacent belts 151 and driven to rotate at a peripheral speed that is slightly higher than the traveling speed of the conveyer belts 151. The shaft carrying the touch rolls 152 is resiliently supported, as indicated by double-headed arrow, and urged so as to make the touch rolls 152 to be in pressing contact with veneer roll 154.
In the above apparatus, veneer reeling is accomplished by rotating the veneer roll 154 by frictional force from the touch rolls 152 pressed thereagainst with a force that is large enough to effect the rotation. Because the veneer roll 154 and the touch rolls 152 are engaged substantially in circle-to-circle contact and hence the length of contact therebetween as seen in veneer conveying direction is rather short, the magnitude of stress resulting from the contact and acting on a unit area between the touch roll 152 and the veneer roll 154 is disadvantageously large. Consequently, the veneer sheet 150 is subjected at the point of contact to a stress that tends to strain or deform the sheet.
On the other hand, a veneer sheet 150 as peeled by a veneer lathe (not shown) comes out therefrom inherently in such a form that the sheet is waved at short intervals. Further, veneer sheet 150 is formed in the lower surface thereof with a number of small cracks, usually called "lathe checks", produced during peeling operation. Thus, veneer sheet generally tends to be deformed easily when it receives an external force. Additionally, because a wood veneer sheet is of heterogeneous quality, such deformation takes place variably from one location thereof to another along the line of contact between the veneer sheet and the touch rolls 152 even when it is subjected to application of the same force.
When subjected to the above straining or deforming stress at the touch rolls 152, veneer sheet 150 is stretched or extended in the region upstream of the touch rolls 152. Because this extension takes place variably from one location to another of the veneer sheet 150 across the direction in which it is moved, sheet movement tends to be deviated from a straightforward course along the belts 151, with the result that veneer sheet 150 may collide against a frame of the reeling apparatus, thus causing a damage to veneer sheet 150. Furthermore, any excessive extension of veneer sheet 150 causes slack in the sheet as indicated by 150a, which may result in formation of folds. If veneer sheet 150 is wound as folded round the roll 154, the sheet is broken at bends of the folds, thereby affecting the veneer quality and yield.